This relates generally to imaging systems, and more particularly to imaging systems performing sharpness measurements.
Modern electronic devices such as cellular telephones, cameras, and computers often use digital image sensors. Imagers (i.e., image sensors) may be formed from a two-dimensional array of image sensing pixels. Each pixel receives incident photons (light) and converts the photons into electrical signals. Imaging systems may require pre-processing and post-processing of images captured by the receipt and conversion of light into electrical signals. Imaging systems may contain image processing circuitry that provides pre-processing and post-processing functionality such as auto focus mechanisms and adaptive image enhancement. During pre-processing and post-processing functions, imaging systems may perform sharpness measurements on desired portions of captured images.
In low light conditions, conventional imaging systems suffer from increased noise, and sharpness measurements performed by the system may be degraded.
Therefore, it would be desirable to design an imaging system with improved sharpness measurements.